5/16/2012

Percent increase is when
you find a given percent
of an amount and then
add it to it.Percent
decrease is when you find
a given percent of an
amount and subtract it
from it.

One really important
thing to remember about
percent increase and decrease
is that percent is always
based on something, it
doesn't stand alone, there
is always something that
it is "of" and with percent
increase and decrease
problems that is always
the ORIGINAL amount.

There
are three kind of
percent increase and decrease
problems and a good first
step towards solving a
problem is to decide which
of them it is:
1.Original amount, percent
known, you want to find
the new amount.If cost of life is running
at 3%, how much would you need to live a year if your
current expenditure is $920
per month?
2.Original amount known,
new amount known, you
want to find out what
percent the increase or
decrease is.The value of Spain exports
to Germany increased
from €1480 million in 1987
to €2768 million in 1988.
What was the percentage
increase?
3.New amount known, percent
known, you want to find
the original amount.An item originally costing
$20 is on a 10% off sale.
What is the sale price?